Bleaching process and composition

ABSTRACT

A BLEACHING PROCESS IN WHICH THE BLEACHING AGENT IS AN AQUEOUS SOLUTION CONTAINING A BENZOYL GLUTARYL PEROXIDE OF THE FORMULA WHEREIN R IS PHENYL OR SUBSTITUTED PHENYL AND AN INORGANIC PERHYDRATE IS DISCLOSED. BLEACHING COMPOSITIONS CONTAINING SUCH PEROXIDES AND PERHYDRATES WITH DETERGENT SALTS AND/OR ORGANIC SURFACE-ACTIVE AGENTS ARE ALSO DESCRIBED.   RCO.OO.CO(CH2)3CO2H

3,756,775 BLEACHING PROCESS AND COMPOSITION Kjell Torsten Nordfalt,Heddon-on-the-Wall, England, as-

signor to The Procter & Gamble Company, Cincinnati, Ohio No Drawing.Filed June 10, 1971, Ser. No. 151,910 Claims priority, application GreatBritain, Mar. 3, 1971, 5,896/ 71 Int. Cl. D061 3/02 US. Cl. 8-111 9Claims ABSTRACT OF THE DISCLOSURE A bleaching process in which thebleaching agent is an aqueous solution containing a benzoyl glutarylperoxide of the formula RCO-OO-CO (CH CO H wherein R is phenyl orsubstituted phenyl and an inorganic perhydrate is disclosed. Bleachingcompositions containing such peroxides and perhydrates with detergentsalts and/or organic surface-active agents are also described.

BACKGROUND OF THE INVENTION This invention relates to a bleachingprocess and to bleaching compositions employing an organic bleachingagent and an inorganic perhydrate.

The bleaching of fabrics and the like with hydrogen peroxide or withinorganic substances yielding hydrogen peroxide in solution is known tothe art and such substances, in particular sodium perborate orpercarbonate, have long been common ingredients of bleaching anddetergent compositions. These bleaching agents are effective attemperatures near the boiling point of water, for example, over about 85C.; however, these substances have little effect at temperatures from 35C. to 65 C.

Certain organic peroxygen compounds have been disclosed as bleachingagents effective at these lower temperatures. One class includes theorganic aliphatic and aromatic peroxycarboxylic acids, and especiallythe more effective aromatic percarboxylic acids such as those describedin US. Pat. 3,075,921 issued Jan. 29, 1963 to Brocklehurst et al. Thesecompounds, however, are generally unstable; they tend to lose theiractivity rapidly in storage, and in some cases may be explosive. Thus,they are difficult to handle in processing and in use. Furthermore, thisinstability is intensified by traces of metals such as iron, nickel,cobalt, copper and the like.

The organic peroxides, and in particular the diacyl peroxides, compriseanother class of peroxygen bleaching agents. Some of these compounds aredescribed in Belgian patent specification 603,768. These substanceshydrolyze in the presence of water to form peroxycarboxylic acids, whichare believed to be the substances actually responsible for the bleachingactivity. The organic peroxides tend to be unstable and in some casesare explosive. Many are only slightly soluble in water, and therefore,hydrolyze slowly at moderate washing temperatures. Thus, little of theactual bleaching agent may be released in the duration of an ordinarywashing process. Dibenzoyl peroxide is an example of an unstable andslightly-soluble peroxide compound.

Benzoyl succinyl peroxide is one of the preferred diacyl peroxides setforth in Belgian specification 603,768; this compound is soluble inwater, under neutral or alkaline conditions. Nevertheless, it isunstable in detergent compositions. Explosivity tests indicate that itmay detonate upon impact. Although detergent compositions are unlikelyto be subjected in ordinary use to the impact applied in an impact test(as described in Example III hereafter), a propensity to detonate undersuch condi- 3,756,775 Patented Sept. 4, 1973 tions indicates that theymay be dangerously unstable under other conditions.

SUMMARY OF THE INVENTION It has now been found quite unexpectedly thatthe benzoyl glutaryl peroxide bleaching agents of this invention arestable in detergent compositions and have a reduced tendency to causecolor or fabric damage when employed in combination with an inorganicperhydrate. In addition, they are nonexplosive, even in the presence ofmetal ions such as iron, nickel, cobalt, copper and the like. In spiteof their improved stability, these benzoyl glutaryl peroxides, beingsoluble in alkaline washing and bleaching liquors, hydrolyze rapidlyduring a washing or bleaching process, forming an aromatic peroxy acidas the effective bleaching agent. The benzoyl glutaryl peroxides are,therefore, very valuable bleaching agents for use at temperatures belowabout they are also effective at higher temperatures.

In its process aspect, the present invention provides a process forbleaching textile materials which comprises treating such materials withan aqueous solution of a benzoyl glutaryl peroxide of the generalformula RCO OO-CO (CH CO H where R is phenyl or substituted phenyl andan inorganic perhydrate.

In its composition aspect, the present invention provides bleachingcompositions containing a benzoyl glutaryl peroxide and an inorganicperhydratc in combination with a detergent salt and/or organicsurface-active agent.

DETAILED DESCRIPTION OF THE INVENTION The benzoyl glutaryl peroxidessuitable herein are those corresponding to the hereinbefore describedformula.

Preferred peroxides are those where the benzoyl radical is unsubstitutedor is substituted by one or more chlorine, methyl or methoxy groups.Suitable substituted benzoyl glutaryl peroxides include m-chlorobenzoylglutaryl peroxide, p-methylbenzoyl glutaryl peroxide, p-methoxybenzoylglutaryl peroxide.

Ordinarily the peroxides of the invention are employed in a solution ata concentration which provides from 1 to 200 p.p.m. by weight ofavailable oxygen in the solution. A preferred concentration is from 5 top.p.m., especially from 10 to 40 ppm.

The benzoyl glutaryl peroxides of the invention can be prepared inaccordance with methods known in the art. Suitable methods ofpreparation include, for example, reaction of an aromatic peroxy acidwith glutaric anhydride in a suitable solvent, or reaction of anaroylchloride with mono perglutaric acid in the presence of anequivalent weight of a base. The preparation of benzoyl glutarylperoxide is disclosed by Zeit f. Physiol. Chemie, 323 pp. 211-235(1961), incorporated by reference herein.

A primary function of an oxidizing bleaching agent is to reactchemically with and to oxidize stains, thereby reducing their color and/or making them more susceptible to washing action. On the other hand,such. agents should not decolorize or alter appreciably dyestuffs (whichmight be considered as intentional stains), or cause damage to fabricsthemselves, but no effective bleaching agent is perfect in theserespects. It has now been found that the tendency of benozyl glutarylperoxides to cause color or fabric damage, and its tendency to causeyellowing of nylon fabrics, is reduced if an inorganic perhydrate, ispresent with it in the bleaching liquor.

By inorganic perhydrates are meant compounds providing hydrogen peroxidein aqueous solution, such as sodium perborate, percarbonate,perphosphate, or hydrogen peroxide itself. Potassium and other suitablesalts can also be used. This mixture provides slightly less bleachingaction than the benzoyl glutaryl peroxide alone but considerably more,at temperature below about 85 C., than perhydrate alone, and provides abetter combination of bleaching effect and lack of color or fabricdamage than is provided by either component alone.

Preferred perhydrates are those named above, especially sodiumperborate. Hydrogen peroxide as such may be used in bleaching liquorsand in the process of the invention. Its use in concentratedcompositions, though Within the scope of the invention, would often leadto ditficulty in obtaining stable products. The amount of perhydrate ispreferably such that the weight ratio of available oxygen in the benzoylglutaryl peroxide to that in the perhydrate is from 3:1 to 1:5,especially in the range 1:1 to 1:5.

In practice, it is usually convenient to incorporate the benzoylglutaryl peroxide and inorganic perhydrate of the invention into ableaching or bleaching and washing composition containing otherdesirable compoents. Such compositions are preferably, but notnecessarily, particulate solids. The compositions can contain inorganicor organic detergent builder salts. They can contain, for example,alkaline inorganic builder salts such as the alkali metal carbonates,silicates, phosphates and polyphosphates. Suitable organic water-solublebuilder salts include the aminopolycarboxylates, particularly sodiumnitrilotriacetates, organic polyphosphonates such asethane-1-hydroxy-1,1- diphosphonates, sodium citrate, sodium gluconateand the like. The builder salts herein are employed in an amount of from1% to 99% by weight of the compositions of the invention. Neutraldiluent salts such as alkali metal chlorides or sulfates can beemployed. Compatible watersoluble organic surface-active agents,including anionic, nonionic, zwitterionic and ampholytic detergents canalso be present, for example, in an amount of up to 90% by weight. Theamounts of these components, i.e., the inorganic or organic buildersalts and organic surface-active agents used, depend on both the natureof the organic detergent and the intended purpose of the products.Normally the proportions of such components will correspond to a weightratio of builder to detergent of from about 30:1 to 1:4, preferably from9:1 to 1:1.

Particularly suitable organic anionic detergents are the water-solublesoaps and the alkyl benzene sulfonates, especially linear alkyl benzenesulfonates, alkyl sulfates, olefin sulfates and other organic sulfatesand sulfonates. Suitable nonionic detergents include the polyethyleneoxide condensates with polypropylene oxides, e.g., the Pluronics (tradename), or with fatty alcohols, alkyl phenols, fatty acids and the like.Suitable detergents herein are those described in US. Pat. 3,351,558 toRoger E. Zimmerer at column 6, line 59 to column 9, line 69,incorporated herein by reference.

The compositions can also contain the usual minor components ofconventional bleaching and washing compositions such as colors, perfume,tarnish inhibitors stabilizers for the bleach, optical brighteners,enzymes, dust preventatives, suds-enhancing or suds-depressing agents,abrasives and the like.

Although the peroxides described hereinbefore are more stable duringstorage in detergent compositions than prior known water-soluble organicperoxy bleaching agents, it is desirable to provide protection fromatmospheric or other moisture and from other components of thecompositions. This can be effected for instance, by coating the peroxidewith an inert material, or by mixing the peroxides with an inert orstabilizing substance and coating the mixture. Alternatively the mixturecan be agglomerated or extruded in the form of noodles, ribbons, flakesor the like. Other suitable methods of providing protection frommoisture can be employed.

The proportion of the benzoyl glutaryl peroxide in the compositions ofthe invention should be such as to provide a concentration of availableoxygen in the ranges defined hereinbefore when the compositions are usedat the intended concentration in a bleaching or washing liquor. Thecompositions intended to be used at conventional concetrations forhousehold washig would normally contain enough benzoyl glutaryl peroxideto provide from 0.1% to 3% by weight of the composition of availableoxygen, preferably 0.2% especially from 0.2% to 1%.

The following examples illustrate the invention:

EXAMPLE I Bleaching eflect Solutions were prepared containing 4 g. perliter of a detergent composition consisting of percent by weight:

Linear alkylbenzene sulfonate (alkyl chain C to C 17.6 Sodium toluenesulfonate 1.8 Sodium tripolyphosphate 46.2 Sodium silicate 7.3 Coconutmonoethanolamide 1.8 Sodium carboxymethylcellulose 1.0 Sodium sulfate12.4 Miscellaneous minor components 1.9 Moisture 10.0

together with EXAMPLE II Stability in detergent composition Thestabilities of a typical aromatic peroxy acid and of benzoyl succinylperoxide and benzoyl glutaryl peroxide when mixed with detergentgranules of composition given in Example I were compared. The percentageloss of active oxygen in 14 days storage at 21 C. in wax laminatedcartons was:

Percent m-Chloro peroxybenzoic acid Benzoyl succinyl peroxide 12 Benzoylglutaryl peroxide 4 m-Chloro-benzoyl glutaryl peroxide 5 EXAMPLE IIIExplosivity Samples were tested in an Impact Testing machine wherein0.02 g. of substance was spread on a die of 1 square cm. area confinedby a plunger of the same area. A 2 kg. weight was dropped on the plungerfrom 150 and 200 cms. In each case benzoyl succinyl peroxide deto nated,benzoyl glutaryl peroxide did not detonate.

EXAMPLE IV Bleaching performance in aqueous solution alone Pieces of teastained cotton cloth were washed for 10 minutes in solutions of thesubstances named below, each at a level to provide parts per millionavailable oxygen, at 50 C. The stain removal values measured as inExample I were:

Percent Benzoyl glutaryl peroxide 49.5 Sodium perborate 3 Dibenzoylperoxide Nil EXAMPLE V Stability in presence of sodium carbonate Equalweights of sodium carbonate and the following peroxides were mixed andstored in wax-laminated cardboard cartons in a laboratory (at about 24C.) for two weeks. The loss of available oxygen, by weight of thatoriginally present was:

Percent (a) Benzoyl glutaryl peroxide 3 (b) m-Chlorobenzoyl glutarylperoxide 3 (c) Benzoyl sucinyl peroxide 39 (d) Dibenzoyl peroxide 13EXAMPLE VI A typical heavy duty detergent in combination with ableaching agent was prepared having the following formula:

Washing and bleaching solutions were made up in tap water (about 175p.p.m. hardness as CaCO containing per liter:

(i) 4.75 g. Composition A 0.25 g. BGP (ii) 4.55 g. Composition A 0.25 g.BGP 0.2 g. PB4 (iii) 4.45 g. Composition A 0.25 g. BGP 0.3 g. PB4 (iv)4.25 g. Composition A 0.25 g. BGP 0.5 g. PB4 (v) 4.15 g. Composition A0.25 g. BGP 0.6 g. PB4

BGP means Benzoyl glutaryl peroxide PB4 means sodium perboratetetrahydrate Stain removal Tea stained cotton swatches were washed inthese solutions in a miniature washing machine at 50 C. for minutes.They were removed, rinsed in cold tap water, dried and their reflectancemeasured and compared with that before washing, percent stain removalbeing measured Reflectance after bleach 100 X Refiectance before bleachloo-Refiectanoe before bleach Values obtained were:

Solution: Percent stain removal (i) 71 (ii) 65 (iii) 64 (iv) 68 (v) 68Fabric damage Test pieces of nylon, cotton, and terylene-cotton mixturewere washed 10 times in solutions (i), (iii) and (v) at 50 C. After eachwash they were rinsed in cold tap water and dried. Fabric damage wasdenoted by loss of tensile strength and the figures given belowrepresent the average percentage loss of tensile strength of all thefabrics.

6 Solution: Percent loss of tensile strength (i) 13 (iii) 9 (v) 10 Nylonyellowing Test pieces of nylon, treated with optical brightener duringmanufacture were placed in solutions (i), (ii), (iii) and (iv) at 50 C.,soaked overnight and allowed to cool naturally to room temperature.Fresh solutions were heated to 50 C. and the fabrics were washed at thistemperature for 10 minutes, rinsed in cold tap water and dried. Thiscycle was repeated 10 times. The whiteness or yellowness of the fabricsbefore and after treatment was measured by means of a Hunter ColorDilference Meter (manufactured by Hunter Associates Laboratorys Inc.) ona scale where increasing negative values indicate increased yellowness.

Values obtained were:

ample VI but containing per liter (vi) 4.25 g. Composition A 0.25 g. BGP0.5 g. PB4 (vii) 4.8 g. Composition A 0.20 g. BGP

Stain removal tests and nylon yellowing tests were conducted as inExample VI. The results were:

Stain removal Solution: Percent (vi) 68 (vii) 67 Nylon yellowingSolution:

(vi) 4 (vii) -22 A level of BGP which gives the same or slightly lessstain removal than mixed BGP/perborate produces yellowing of nylon.

What is claimed is:

1. A process for bleaching textile materials which comprises treatingsuch materials with an aqueous solution of benzoyl glutaryl peroxide ofthe formula RCO OO-CO (CH CO H wherein R is phenyl or phenyl substitutedwith one or more Cl, --OCH or CH radicals; and an inorganic perhydratecapable of providing hydrogen peroxide in said solution and providing aweight ratio of available oxygen from the benzoyl glutaryl peroxide tothat of the inorganic perhydrate of from 3:1 to 1:6.

2. The process of claim 1 wherein R is phenyl.

3. The process of claim 1 wherein the benzoyl glutaryl peroxide ispresent at a concentration sufiicient to provide from 1 to 200 parts permillion by weight of available oxygen in solution.

4. The process of claim 1 wherein the benzoyl glutaryl peroxide ispresent at a concentration suflicient to provide from 10 to 40 parts permillion by weight of available oxygen in solution.

5. The process of claim 1 wherein the inorganic perhydrate is selectedfrom the group consisting of sodium perborate, sodium perphosphate andsodium percarbonate.

6. The process of claim 4 wherein the weight ratio of available oxygenof said benzoyl glutaryl peroxide to that of said perhydrate is from 1:1to 1:6.

7. A bleaching composition consisting essentially of a mixture of awater-soluble organic detergent selected from the group consisting ofanionic, nonionic, zwitterionic and ampholytic detergents andwater-soluble inorganic or organic detergency builder salt in a ratio ofbuilder salt to detergent of from 30:1 to 1:4, a benzoyl glutarylperoxide bleaching agent of the formula RCO OO CO (CH2) 3CO H 8 8. Thebleaching composition of claim 7 wherein R is phenyl.

9. The bleaching composition of claim 8 having sufficient benzoylglutaryl peroxide to provide from 0.1% to 5 3% by weight of thecomposition of available oxygen.

References Cited UNITED STATES PATENTS 3,026,166 3/1962 Gallagher 8111MAYER WEINBLATI, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat nt 3.756.775Dated September 4, 1973 Inventor(s) Kjell Torstenn falt It is certifiedthat errorappears in the above-identified patentand that said LettersPatent are hereby corrected as shown below:

Column 3, line 4 "temperature" should read --temperatures- Column 3,line 16 "125" and "125" should read -l.'6 and -lI4 respectively Column3, line 20 "compoents" should read components Column 5, line 12"sucinyl" should read succiny1 Column 7, line "substituted" should read-phenyl substituted- Signed and sealed this 10th day of September 197A.

(SEAL) Attest:

MCCOY M. GIBSON, JR; c. MARSHALL DANN Attesting Officer a Commissionerof Patents.

FORM PO-lOSO (10-69) STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patnt NO- 3.756, 775 I Dat September i, 1973 Inventor) Kjell TorstenNordfalt It is certified that error-appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 4 "temperature" should read -tem'peratures Column 3, line16 "1:5" and "1:5" should read -1.'6- and -lI4- respectively 4 Column 3,line 20 "compoents" should read components Column 5, line 12 "sucinyl"should read -succinyl Column 7, line "substituted" should read -phenylsubstituted-r- Signed and sealed this 10th day of September 197 A (SEAL)Attest:

McCOY M. GIBSON, JR. c. MARSHALL DANN Attesting Officer t Commissionerof Patents.

FORM PO-105O (10-69! USCOMM-DC 60376-P69 a u.s. GOVERNMENT Inm'fmsOFFICE: I969 O36633

